Field of the Invention
The present invention relates to a liquid crystal display device capable of displaying two dimensional displays or three dimensional (stereo image) displays, a substrate for a liquid crystal display device and a manufacturing method of the substrate for a liquid crystal display device.
Discussion of the Background
A liquid crystal panel included in a general liquid crystal display has a configuration in which a liquid crystal layer is sandwiched by two substrates. The two substrates include, for example, a transparent substrate such as glass. A polarizing plate, or a polarizing plate and a phase difference plate are disposed on the front side and the back side of the liquid crystal display.
A liquid crystal display device capable of displaying three dimensional displays or capable of controlling a viewing angle emits light by using a backlight unit or an external light source. The liquid crystal display device capable of displaying three dimensional displays or capable of controlling viewing angle controls, based on a purpose of the display, an angle of the light emitted from the front surface of the liquid crystal panel towards an observer side (external side).
In a liquid crystal display device or a display apparatus capable of displaying three dimensional displays, various display methods are employed. The three dimensional display includes, for example, methods using glasses and methods not using glasses. Methods using glasses include, for example, an anaglyph method in which color differences are utilized or a polarized glasses method in which polarization is utilized. In methods using glasses, the observer is required to wear dedicated glasses, which causes discomfort to the observer. Therefore, in recent years, for three dimensional displays, methods not using glasses have been more popular.
To adjust the angle of the emitted light from the liquid crystal display to a single observer (hereinafter may be referred to as a stereoscopic type) or to a plurality of observers (hereinafter may be referred to a multi-eye type), a technique in which an optical control element is disposed on the front surface or the back surface of the liquid crystal display panel has been considered. In the liquid crystal display device where a method not using glasses is applied, the optical control element may be used.
As an example of the optical element, optical lenses are arranged two dimensionally, and lenticular lenses that accomplish regular refraction are used. The lenticular lens may be formed by processing a transparent resin to be in a sheet shape. In this case, the lenticular lens is employed while attached to the front surface or the back surface of the liquid crystal display device.
The patent literature 1 (Japanese Patent Number 4010564), and patent literature 2 (Japanese Patent Number 4213226) disclose a three dimensional display technique by using a lenticular lens or a lenticular screen. In the patent literature 1, a display element (pixel or sub pixel) is formed in a parallelogram shape or a triangular shape, or a display element is arranged with offset to substantially produce an angle between an arrangement of pixels or sub pixels and a lenticular lens or a lenticular screen. In the patent literature 1, similar to patent literature 2, there is a continuous (smooth) horizontal parallax to the observer. However, in patent literature 1, by a pixel arrangement in which pixels are arranged substantially in oblique and an edge of the lenticular screen that intersects this pixel arrangement, irregularities may occur on the display.
The patent literatures 3 to 8 (Japanese Patent Application Laid-Open Publication No. 2010-506214, Japanese Patent Application Laid-Open Publication No. 2010-524047, Japanese Patent Application Laid-Open Publication No. 2010-541019, Japanese Patent Application Laid-Open Publication No. 2010-541020, Japanese Patent No. 4655465 and Japanese Patent No. 3930021) disclose a prism sheet provided with a convex lens.
Patent literature 9 (Japanese Patent Application Laid-Open Publication No. 2010-210982) discloses a parallax barrier for three dimensional display to the naked-eye. In paragraphs [0016] and [0060] of patent literature 9, it is disclosed that necessary intervals for three dimensional display are secured between the parallax barrier and a color barrier by a configuration in which a light transmission film is formed between the parallax barrier and the color barrier.
Patent literature 9 discloses that the parallax barrier is conductive, however, having an aperture ratio increase is not disclosed because of a relationship between a black matrix being usually formed at the color filter and this parallax barrier. For example, in FIG. 9 of the patent literature 9, the parallax barrier is formed at a location where a part of pixels (B, G, R) are overlapped and the transmittance is likely to decrease. In addition, in FIG. 10 which is considered as a pixel cross section of patent literature 9, a black matrix 41 is illustrated. Since the parallax barrier is formed to cross a color filter 6, it is considered that the transmittance may be decreased. According to the configuration of the parallax barrier described in the patent literature 9, since the parallax barrier is electrically conductive, it is difficult to implement in-cell type electro capacitive touch sensing.
The parallax barrier which is explained in patent literature 9 should be conductive as a necessary requirement. As described in the paragraphs [0025] and [0054] of the patent literature 9, the parallax barrier is formed by using a metal thin film such as chrome or aluminum. According to a film forming method of the parallax barrier in the patent literature 9, it is considered that high manufacturing cost will be required. Further, in a manufacturing method for forming the black matrix 41 having light shielding properties, how to perform the alignment thereof is not examined. Usually, a black matrix contains color material having light shielding properties such as carbon pigment with high density and similarly, the parallax barrier may have light shielding properties. Thus, in a case where the black matrix and the parallax barrier have the light shielding properties, performing a photo alignment may be difficult.
Patent literature 1: Japanese Patent Number 4010564
Patent literature 2: Japanese Patent Number 4213226
Patent literature 3: Japanese Patent Application Laid-Open Publication Number 2010-506214
Patent literature 4: Japanese Patent Application Laid-Open Publication Number 2010-524047
Patent literature 5: Japanese Patent Application Laid-Open Publication Number 2010-541019
Patent literature 6: Japanese Patent Application Laid-Open Publication Number 2010-541020
Patent literature 7: Japanese Patent Number 4655465
Patent literature 8: Japanese Patent Number 3930021
Patent literature 9: Japanese Patent Application Laid-Open Publication Number 2010-210982